1. Field of the Invention
The present invention relates to practice golf clubs and more particularly, but not by way of limitation, to a practice club which is particularly designed and constructed to duplicate the swing characteristics of its representative golf club and which is provided with a striking face which is substantially identical in size, shape, and position to that of the sweet-spot area of the representative golf club for providing a golfer with a practice club to aid in developing a grooved accurate swing. The present invention is even more particularly, but not by way of limitation, designed for the use of light weight practice balls to enhance a golfer's swing while substantially reducing the possibility of the development of bad swing habits due to the light weight of the said practice balls.
2. Description of the Prior Art
It has long been recognized in the art that at a particular location of every golf club face there is a spot which is referred to in the art as "the club sweet-spot". The sweet-spot in the club is defined as the point on the club whereupon contact with the ball will not produce a twisting motion of the club and therefore will result in the maximum true flight of the golf ball with a minimum of vibration, jar, or twisting of the club itself. This sweet-spot would be more accurately defined as a spot on the club face coinciding with the center-of-percussion of the club when swung about an area coinciding with the handle grip of the club. It is therefore the desire of every golfer to develop a grooved swing so that the golf club head will strike the ball at a point on or very near the club sweet-spot.
This sweet-spot for a particular club may be found by any number of ways, the most common being that of suspending the club from the grip end and gently tapping the club face with a sharp object until a point is found thereon wherein the club will tend to rebound straight back without any twisting being detected at the club grip. However, since the sweet-spot or center of percussion on the face of the club will move slightly depending upon the radius of swing of the club, a more accurate method would be to utilize a mechanical golf club swing machine in determining the point of contact with the ball which results in maximum flight of said ball.
Since in practice it would be impossible to consistently strike the ball at the particular club sweet-spot it is important to determine a sweet-spot area which will be defined as that striking area which will produce a golf ball flight which is within ten percent of that flight produced by striking the ball at the sweet-spot.
This sweet-spot area for purposes of description herein may be closely represented by an elliptical shape having a horizontally disposed major axis length of approximately 1.84 inches and a vertically disposed minor axis length of approximately 1.275 inches. Naturally this area could be less accurately duplicated by a circular area having a diameter of approximately 1.275 inches. These figures are particularly suited for the MacGregor Tourney Driver, Lite 2. It is pointed out that the sweet-spot area shape and size will vary somewhat among commercially available golf clubs due to shaft stiffness, torsion characteristics, weight and club design but seldom is less than 15% nor more than 60% of the area of the club face.
One of the primary problems in the utilization of light weight practice balls is that after the golfer has spent much time utilizing the practice balls, he finds, upon using regulation or legal golf balls, that he has developed some other equally bad habits which did not show up by the use of the light practice balls. This is often due to the fact that the practice ball being so light may be struck at some point on the club face remote of the sweet-spot which will give the light practice ball a true flight whereas when a commercially available standard weight golf ball is struck at the same point a twisting motion is induced into the club thereby causing the ball to deviate from the optimum trajectory which decreases the accuracy of the ball and the range thereof.
One attempt to solve this problem was provided by the patent to Sabia, U.S. Pat. No. 3,126,206, issued in 1964, and entitled "PRACTICE GOLF CLUB AND TETHER BALL". The Sabia practice golf club utilized a standard golf club having an area about the sweet-spot of the club removed thereby forming a groove which is perpendicular to the striking face of the club whereby upon a perfect swing in relation to the tether ball, the club would simply pass the tether ball without touching it. This method has several disadvantages, one being that by removing a portion of the golf club the weight thereof is changed thereby changing the swing characteristics of the club for which the practice club is to represent. Naturally, extra weights could be added to bring the weight of the practice club equal to the weight of its representative club but this would not compensate for the second disadvantage, that being of failure to compensate for the wind resistance change caused by removing the afore described groove therefrom. Further, unless an exceptionally large groove is removed from the club it would be necessary for the golfer, in order to prevent the tether ball from swinging, to make an exact swing so that no part of the club would strike the ball. This is an unnecessary penalty on the golfer since often a good ball flight may be obtained by striking the ball near the sweet-spot or in the aforementioned sweet-spot area.
A second attempted solution was provided in the patent to Hasten, Jr., et al., U.S. Pat. No. 3,437,341, issued in 1969, and entitled "PRACTICE GOLF CLUB". The Hasten, Jr. device consists of the bolting onto the club face, a disc which extends outwardly from the club face and could be shaped to represent a club sweet-spot area. However, the addition of the disc and the attachment bolts would tend to change the club weight which would in turn change the swing characteristics of the practice club from that of the golf club for which it is to represent and further protrudes beyond the plane of the striking face of the said representative club. It is further noted that if the Hasten Club is utilized with the light weight plastic practice balls a practice ball might be struck at a point on the club face separate from the raised point and still obtain a true flight on the light weight plastic ball thereby giving the golfer a false indication of having obtained a swing grooved on the sweet-spot.